Question

1. how many significant figures are in each of the underlined numbers? a. 60 s = 1 min - b. 47.70 g of copper - c. 129010 g of carbon - d. 404 m - e. 0.0010 nm - f. 23.000 g -

Explanation:

Part a: 60 s = 1 min

Step1: Recall significant figure rules for trailing zeros without a decimal.

Trailing zeros in a whole number without a decimal are ambiguous, but in a conversion factor like this (where 60 is exact? Wait, no, 60 s to 1 min: if it's 60 (not 60.), trailing zero may be non - significant. Wait, actually, in 60, the non - zero digit is 6, and the zero is a trailing zero without a decimal. So significant figures: 1 (the 6). Wait, no, maybe the problem considers 60 as having one significant figure? Wait, no, let's re - check. The rules: non - zero digits are significant. Zeros between non - zeros are significant. Trailing zeros in a number with a decimal are significant. Trailing zeros in a number without a decimal are not significant (they are placeholders). So 60: 6 is significant, 0 is a placeholder. So 1 significant figure? Wait, but sometimes, if it's written as 6.0×10¹, it would be two, but 60 is one. Wait, maybe the problem has 60 as two? No, no. Wait, the number is 60. Let's see: 6 is significant, 0 is after, no decimal. So 1 significant figure? Wait, maybe I made a mistake. Wait, the rule for trailing zeros: in 60, the zero is a trailing zero in a whole number. So it's not significant. So 60 has 1 significant figure.

Step2: Confirm.

Non - zero digit 6, zero is trailing without decimal. So significant figures: 1.

Step1: Recall significant figure rules for decimals.

All non - zero digits are significant (4,7,7). Zeros after the decimal and after a non - zero digit are significant. So in 47.70, 4,7,7,0 (the last zero) are significant.

Step2: Count.

4 (1), 7 (2), 7 (3), 0 (4). So 4 significant figures.

Step1: Recall rules for trailing zeros without decimal.

Non - zero digits: 1,2,9,0,1,0. Wait, zeros between non - zeros are significant (the 0 between 9 and 1 is significant). Trailing zero (the last 0) is not significant. So non - zero digits: 1,2,9,1 and the zero between 9 and 1.

Step2: Count.

1 (1), 2 (2), 9 (3), 0 (between 9 and 1, 4), 1 (5). The last zero is a placeholder. So 5 significant figures.

Answer:

1

Part b: 47.70 g of copper